#include <stdio.h>
#include <stdlib.h>

/*哪个大夫哪天值班*/

int a[8];
char *day[]=
{
    " ","MONDAY","TUESDAY","WEDNESDAY","THURSDAY",
    "FRIDAY","SATURDAY","SUNDAY"
};

void main()
{
    int i,t,j;
    a[4]=6;
    for(i=1;i<=3;i++)
    {
        a[i]=2;
        if(!a[i+3]) a[i+3]=7;
        else {
            a[i]=0; continue;
        }
        for(t=1;t<=3;t++)
        {
            if(!a[t]) a[t]=5;
            else continue;
            if(!a[t+2]) a[t+2]=4;
            else {  a[t]=0; continue;}
            for(j=5;j<7;j++)
            {
                if(!a[j]) a[j]=3;
                else continue;
                if(!a[j+1]) a[i+1]=1;
                else {  a[j]=0;continue;}
                for(i=1;i<=7;i++)
                printf("Doctor %c is on duty %s.\n",'A'+a[i]-1,day[i]);
                exit(0);
            }
        }
    }
}
